Electrically driven track wheels for tracked vehicles

ABSTRACT

An electrically driven wheel for a tracked vehicle which includes a driving track wheel with built in cogs and a brushless DC motor having a mounting shaft to connect the wheels to the tracked vehicle. The brushless DC motor is coupled within the driving track wheel to develop rotational torque for rotating the driving track wheel and includes a drum, a bank of pole assemblies connected between the drum and the stationary mounting shaft, and electrical wiring for energizing the bank of pole assemblies. In an embodiment, the brushless DC motor includes permanent magnet high multiple pole motors. The electrically driven wheels are part of a drive system for the tracked vehicle. The drive system includes a track module frame, at least two flexible tracks coupled with the electrically driven track wheels, and a controller for controlling the electrically driven track wheels in response to a driver command.

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 11/454,198 filed on Jun. 16, 2006 now U.S. Pat. No.7,343,991, now allowed.

This invention claims the benefit of priority to U.S. Provisional PatentApplication No. 60/776,778 filed on Feb. 24, 2006.

FIELD OF THE INVENTION

This invention relates to vehicles, in particular to environmentallyfriendly electrically driven track wheels for tracked vehicles, andrelated devices, apparatus and methods of operation thereof.

BACKGROUND AND PRIOR ART

Oil exploration has been difficult in sensitive environments such as theNorth Slope of Alaska since current vehicles can damage and destroythose environments. For example, vehicles having separate wheels cancause deformation to the ground and gouging of the ground surface whilebeing operated. It is highly desirable under certain environmentallysensitive conditions to have a tracked vehicle which causes the leastdeformation of the ground as possible. Such uses include operationacross frozen tundra typical of the ANWR region of the North Slope ofAlaska.

While wheeled vehicles typically have highly refined independentsuspension systems, tracked vehicles have been limited to rigid,non-compliant suspension systems. This has been a necessity partly dueto the driving track wheels being rigidly mounted to the power train.Because of this rigid mounting, the vehicle causes the ground to conformto the track system, rather than the other way around.

Most tracked vehicles are powered by mechanically driven track wheelswhich are prone to problems. Tracked wheels are not known to haveindependent suspensions. Although better than separate wheeled vehicles,traditional tracked wheels such as those found on tractors, militaryvehicles and the like, have been also known to damage and gouge a groundsurface.

U.S. Pat. No. 5,533,587 issued to Dow et al. on Jul. 9, 1996 disclosesan articulated tracked vehicle for agricultural harvesting which reducesdamage to fields and can be driven on paved roads at reasonable speeds.The vehicle has front and rear elements, linked by an articulating jointwhich permits turning and rotation of one element with respect to theother. Each element is motivated by a pair of tracked power units whichare hydraulically driven by a heavy duty differential between the units.Each power unit is rotatably mounted solely on a shaft sleeve of thedifferential and is free to oscillate vertically and independently toabsorb irregularities in its path. Each unit includes an endlesselastomeric track which has two rows of lugs on its inner surface. Anovel drive mechanism engages these lugs to motivate the vehicle. Asealed transmission housing in each power unit protects key driveelements from environmental damage without interfering with operation ofthe unit. The transmission is centrally disposed within each power unitto provide further protection from damage.

U.S. Pat. Nos. 6,044,921 and 6,220,377 issued to Lansberry on Apr. 4,2000 and on Apr. 24, 2001, respectively, describes a vehicle with adriving track assembly and a pair of secondary driving assembliesdisposed on opposing lateral sides of the track. Each secondary drivingstructure includes a ground engaging wheel. The driving track assemblyincludes an endless ground engaging track that drives the vehicle. Theflanking driving structures also engage the ground and are rotated toimpart force to the vehicle. A steering device is operatively connectedto the secondary driving assemblies so as to affect a vehicle steeringoperation, wherein the ground engaging driving structures are operatedto turn said vehicle with respect to said vehicle driving direction.Preferably, the force imparted to the vehicle by one of said groundengaging driving structures is greater than the force imparted to thevehicle by the other of the ground engaging driving structures, therebycausing the vehicle to turn with respect to the vehicle drivingdirection.

The '377 includes a secondary driving and steering structure includes aground engaging driving and steering structure that is preferably aground engaging wheel wherein the steering device is operativelyconnected to the secondary driving and steering assemblies. Preferably,the steering device control is operable to transfer a substantialportion of the load support from the central driving track assemblyduring straight ahead movement onto the secondary driving and steeringassemblies during turning movements.

The Lansberry patents relate to vehicles for use on a wide range ofterrain, including uneven and/or steep terrain having a variety of soilconditions. They also describe use of DC magnet motors for driving andalternate version of the vehicle. The DC permanent magnet motors thathave a transmission incorporated in the motor, has fewer than ten movingparts and the transmission portion ensures that sufficient torque isavailable for rugged terrain.

However, the prior art fails to provide a track system that conforms tothe ground, rather than the other way around. What is needed is avehicle having a track system including electrically controlled wheelsso that when the vehicle is traveling on environmentally sensitiveterrain the vehicle causes the least deformation of the ground aspossible.

SUMMARY OF THE INVENTION

A primary objective of the present invention is to provide trackedvehicle, and related apparatus, devices and methods of operating thetracked vehicle where the driving track wheels are not mechanicallyconnected to the power train, or to the main physical frame of thevehicle.

A secondary objective of the present invention is to provide trackedvehicle, and related apparatus, devices and methods of operating thetracked vehicle which causes the least deformation of the ground aspossible, and is most useful in environmentally sensitive areas such asthe frozen tundra typical of the ANWR region of the North Slope ofAlaska. By using a completely compliant, independent suspension of atracked vehicle, it is possible to operate under sensitive conditionswith a very low footprint signature, which minimizes any deformation tothe environment.

A third objective of the present invention is to provide trackedvehicle, and related apparatus, devices and methods of operating thetracked vehicle which uses electrically driven, direct drive PMbrushless DC motor contained within the actual driving track coggedwheel and requiring no gearbox.

The novel tracked vehicle has many features/advantages such as:

1. Fully articulated for less damage to frozen tundra, sensitive soilconditions.

2. Direct drive motor inside track wheel, needing no gearbox ortransmission.

3. Track directly driven by cogged track wheel.

4. Four track wheels each electrically powered to distribute stress intrack for less environmental disturbance.

5. Track wheel motors are permanent magnet high multiple pole forprecise track control and sync.

6. Two independent motors and electronic drives per track allow get-homecapability in event of failure of a single drive motor or electronicdrive or related components.

7. Motor is “inside out”—shaft is stationary, outer case turns—forsimplified installation and elimination of gear boxes.

8. Motor end plates directly mount track wheel and transmit thrust loadsdirectly to motor bearings and to mounting shaft—main drum sees nothrust loads, only develops rotational torque.

9. Full torque is available in either direction.

10. Control system allows automatic protection against overload, overcurrent, over speed, too tight turns at high speed, top speed vs.G-loads of rough terrain.

11. Motor is sealed, pressurized with inert gas for water protection.

12. Motor is cooled/heated with liquid coolant, such as Freon etholenegycol, etc.

13. Electric drive track assemblies permit increased and adjustableground clearance.

14. Special permanent magnet material and mounting permit operations aslow as +50 degrees C. and as high as +50 degrees C.

15. Hollow axle shaft assembly permits wiring and coolant lines tooperate motor through non rotating part of motor, and allow motor to besealed against environment.

16. No oil spills or water contamination.

17. Permanent magnet electric motor drive allows efficiency over 95%without traditional heat losses to clutches, gear boxes, differentials,hydraulics, etc., for less heat loss to affect environment by meltingfrozen tundra. Motor temperature stays very close to ambient.

A first embodiment of the present invention provides an electricallydriven wheel for a tracked vehicle. The electrically driven wheelsincludes a driving track wheel with built in cogs on an outer surfacefor driving a track and a brushless DC motor having a stationarymounting shaft for connecting the electrically driven wheel to a frameof the tracked vehicle, wherein the brushless DC motor is coupled withinthe driving track wheel to develop rotational torque for rotating thedriving track wheel. End plates covering each end of the driving trackwheel enclosing the brushless DC motor, wherein the driving track wheeldirectly transmits thrust loads directly to the mounting shaft. Thebrushless DC motor includes a drum having an interior and an exteriorsurface, a bank of pole assemblies connected between the interiorsurface of the drum and the stationary mounting shaft, and electricalwiring for energizing the bank of pole assemblies, wherein theelectrical wiring is routed through a hollow portion of the stationarymounting shaft between said brushless DC motor and a tracked vehiclecontroller. In an embodiment, the brushless DC motor includes permanentmagnet high multiple pole motors for precise track control andsynchronization.

A second embodiment of the present invention provides drive system for atracked vehicle. The drive system includes a track module frame forconnecting the drive system with a chassis of the tracked vehicle, atleast four electrically driven track wheels connected with the trackmodule frame, at least two flexible tracks each coupled with two of theat least four electrically driven track wheels, wherein each of the atleast two flexible tracks travel around the corresponding twoelectrically driven track wheels, and a controller for controlling theat least four electrically driven track wheels in response to a drivercommand.

In an embodiment, the at least one drive system is connected to thetracked vehicle chassis to provide independent control for verticalmovement, tilting (angular) movement and torsional movement and anadjustable height control for adjusting a ground clearance of the trackvehicle to compensate for different terrain slopes to provide asmoother, safer ride, with bump absorption, improved stability, and afaster allowable speed of navigation over uneven surfaces.

Further objects and advantages of this invention will be apparent fromthe following detailed description of the presently preferredembodiments which are illustrated schematically in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a tracked vehicle using the electricallydriven wheels according to the present invention.

FIG. 2 is a perspective view showing the frame with suspension systemand electrically driven wheels of FIG. 1.

FIG. 3 is an exploded view of the wheels shown in FIG. 2.

FIG. 4 is a side view of the track, driving track wheels and paralleltrack module frame connected with the tracked vehicle chassis.

FIGS. 5 a and 5 b show three-quarter angle perspective views of theinside and outside end plates of the electrically driven wheel showingthe motor mounting shaft extending through the center

FIGS. 5 c and 5 d show left and right end views of the brushless DCmotor corresponding to the side views shown in FIGS. 5 a and 5 b,respectively.

FIG. 5 e shows a top view of the wheel.

FIG. 6 is an enlarged perspective side view of the brushless DC motorshown in FIGS. 5 a through 5 e.

FIGS. 7 a and 7 b are cross sectional side views of the brushless DCmotor shown in FIG. 6 sliced perpendicular to the wheel mounting shaftfor a double and a single pair stator.

FIG. 8 is another cross sectional perspective side view of the brushlessDC motor shown in FIG. 6 sliced parallel to the wheel mounting shaft.

FIG. 9 is an exploded view showing the parts of the brushless DC motorshown in FIG. 7 a.

FIG. 10 is a schematic block diagram of the motor and control systemused with the vehicle shown in FIG. 1.

FIGS. 11 a and 11 b are rear and side views, respectively, of an exampleof a pilot control stick connected with the control system.

FIG. 11 c is a schematic diagram of control stick connected with thecontrol system.

FIG. 12 shows the Low Speed/High Torque configuration of the controlsystem.

FIG. 13 shows the High Speed/Half Torque configuration of the controlsystem.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before explaining the disclosed embodiments of the present invention indetail it is to be understood that the invention is not limited in itsapplications to the details of the particular arrangements shown sincethe invention is capable of other embodiments. Also, the terminologyused herein is for the purpose of description and not of limitation.

100 tracked vehicle 220 built in cogs 200 parallel track module frame300 vehicle chassis frame 205 track module frame side 400 vehiclesuspension 210 electrically driven wheels 416 mounting plate 212 drivingtrack wheel 420 curved suspension plate 214 brushless DC motor 425 cover216 motor mounting shaft 500 track 217 spacer 610 bank of magnets 218hollow core 615 pole 620 mounting disk 714 master motor controllers 630inner end plate 730 pilot control 635 outer end plate 740 electricalpower source 650 outer drum 745 batter pack 655 inside of outer drum 750brake controller 700 drive control electronics 755 braking resistor 702front sensors 800 pilothouse 704 rear sensors 810 pilot controller 712slave motor controllers

FIG. 1 is a perspective view of a tracked vehicle using the electricallydriven wheels and FIG. 2 is a perspective view of the electricallydriven wheels connected with the suspension system and frame of thetracked vehicle shown in FIG. 1. As shown in FIG. 2, the suspensionsystem 400 is connected with the vehicle chassis frame 300 and the trackmodule frame 200. The electrically driven wheels 210 are connected tothe curved endplates 420 of the track module frame 200.

FIG. 3 is an exploded perspective view of electrically driven wheels 210and track module frame 200. As shown, the electrically driven wheels 210includes a brushless DC motor 214 having a motor stationary mountingshaft 216 extending through the motor 214 for connecting theelectrically driven wheels 210 with the track module frame 200. Thetrack module frame 200 includes mounting holes 416 for connecting themotor stationary mounting shaft 216 of the electrically driven wheels210 to the parallel track module frame 200 of the vehicle 100 which isconnected to the vehicle chassis 300 via the suspension system 400. Theground clearance is greatly increased and can be made to be adjustableand can be changed at will, and can be individually varied to compensatefor terrain slope.

As shown in FIG. 3, a direct drive, sealed, PM brushless DC Motor 214 iscontained within driving track wheel 212. Parallel track module frames205 bolt to both ends of the motor stationary mounting shaft 216 of thebrushless DC motor 214. The left and right curved suspension attachplates 420 of the parallel track frame 200 includes mounting holes 416for bolting each one of the motor stationary mounting shafts 216 betweenparallel left and right sides 210 of the track module frame 200.

FIG. 4 shows a side view of a front and rear electrically driven wheel210 and parallel track frame 200 connected with the vehicle chassisframe 300. The track 500 is located between the top cover 425 of thetrack module frame 200 and the driving track wheel 212 of correspondingfront and rear electrically driven wheels 210 which drive the track 500.The tracks 500 are driven by the self contained direct drive brushlessDC motors 214 contained within the track driving wheel 212 which is an“inside out” configuration, wherein the central mounting shaft 216 isstationary and the outside of the brushless DC motor 214 turns.

The driving track wheels 212 are suspended using a suspension systemconfiguration to allow each driving wheel 212 to have independentvertical movement, tilting (angular) movement, and torsional movement.This results in the track belt 500 having less stress which allows thetrack belt 500 to “give” or “follow” when encountering a high spot onthe terrain instead of crushing the high spot with high concentration ofvehicle weight on the high terrain spot.

By enclosing two track driving wheels 212 with integral brushless DCmotors 214 or one track driving wheel and one idler wheel on a trackframe module 300, the torque of the motor is distributed within thetrack frame module 300 in a self contained driving unit. The actualtrack 500 can be made of low temperature flexibility rubber tracks, orof special steel tracks, or of other materials as are well known in theart for use in non-uniform and/or environmentally sensitive terrain. Theactual track 500 can be selected to have the ability to resilientlytrack uneven surfaces rather than flattening out the high spots, thusincreasing track life and minimizing the disturbance to the terrain.This is especially important when traveling across environmentallysensitive terrain such as the tundra.

In the preferred embodiment, the track driving wheels 212 are powered byinternal direct drive pulse modulated (PM) direct-current (DC) integralmotors 214 to deliver twice the power to the ground and to evenlydistribute the actual tensile stress on the track belt. As shown in FIG.3, each track driving wheel 212 includes 360 degrees of built in clogs220 for driving the track 500. Using this configuration, each trackdriving wheel 212 has over 180 degrees of contact between the built incogs 220 and mating belt cogs (FIG. 4) on the inner surface of the track500.

Two or more track frame modules 200 are used to power a completevehicle. Additional track frame modules 200 can be used to powertrailers or additional vehicles connected in tandem with the vehicle,making up a trailer train. By suspending the two or more track moduleframes 200 from the chassis 300 of the main vehicle 100, shocksencountered by the track frame modules 200 are not transmitted to thevehicle chassis frame 300. Additionally, the vehicle has a smoother,safer ride, with bump absorption, improved stability, and a fasterallowable speed of navigation of uneven surfaces. The electricallydriven wheels 210 connected to the vehicle chassis 300 using an advancedsuspension system varies the amount of pressure in the individualsuspension components, increase the ride height and ground clearance andprovides a vehicle wherein tilt compensation can be adjusted andcorrected.

By making the track frame modules as a self contained module, thevehicle has several advantages over the prior art. For example, thetrack frame modules can be made as interchangeable units, thus reducingparts count and lowering manufacturing cost and they can be shippedseparately from the main vehicle chassis, reducing the total width tocommonly acceptable allowable common carrier shipping widths. In theUnited States this is often twelve feet (12′) without undue restriction.Upon reaching the destination, the vehicle can be easily reassembled toits total width, which may be twenty feet (20′) or more. Alternatively,the track frame module can be changed as a complete spare assembly ifrequired, which is advantageous in extremely cold or otherwise hostileenvironments. Another advantage provided by the track frame module withparallel frame sides is the balancing of loads with in the module itselfand driving motor torque is reacted to a very long track frame module.

As shown in FIG. 4, the track belt can be guided by the sides of theparallel track frame to reduce or eliminate the possibility of the beltbecoming derailed from the driving track wheels 212. The belt tensioncan be regulated and adjusted by moving one of the track wheels 212 withintegral driving motor 214 closer or further away from the other trackwheel 212. This can be accomplished with hydraulic cylinders, pneumaticcylinders for air bags, powered jackscrews or manual jackscrews, inconjunction with sliding members coupled with the vehicle chassis frame.Additionally, the parallel frame sides 210 can be made to possesstorsional compliance to allow each track wheel 210 to tilt at adifferent angle according to the localized terrain irregularitiesencountered.

The present invention centers around the electrically driven, directdrive PM brushless DC motor 214 contained within the actual drivingtrack cogged wheel 210. According to the present invention, thebrushless DC motor 214 is enclosed completely within the driving trackwheel 212, to directly drive the track wheel 210 without need forgearboxes to provide starting torque in excess of 30,000 foot pounds, toprovide a wide speed range, efficiency over 95%, to operate from −50 cto +50 c, to be sealed against water and other contaminants, to operatewithout ordinary maintenance, to allow extreme precision of speedcontrol and torque matching between motors, and to tolerate very highG-loads.

FIG. 5 a through 5 e show alternative views of the brushless DC motor214 of the electrically driven wheels 210. FIGS. 5 a and 5 b showthree-quarter angle perspective views of the inside and outside endplates 630 and 635 of the electrically driven wheel 214 showing themotor mounting shaft 216 extending through the center. FIGS. 4 c and 4 dshow the corresponding inside and outside end views of the brushless DCmotor 214 and FIG. 4 e shows a top view of the brushless DC motor 214.

In the preferred embodiment, the end plates of the motor are CNCmachined from steel billet, for maximum strength and the end platessupport the entire weight of the vehicle, but are only subjected toradial static loads, not any torsional loads. The inner and outer endplates 630 and 635, respectively, are machined differently to accept theinner and outer races of the track wheel 212, which bolts to the motorend plates. Thus, the weight of the vehicle is transmitted through thewheel 210 to the end plates, to the motor bearings, to the mountingaxles (shaft) 206, to the track assembly frames 200.

Permanent Magnet PM brushless motors were first described in a researchpaper published in 1962, but practical applications awaited morepowerful magnets, and more sophisticated electronic control systems.Now, the technology exists to make large, powerful and efficient PMBrushless motors. The present invention uses permanent magnet DCbrushless motors for driving the wheels of a vehicle.

FIG. 6 is a perspective view of an example of a brushless DC motor 212with a stationary mounting shaft 216 for connecting the brushless DCmotor 210 to the track module frame 200. FIGS. 7 a and 7 b areperspective cross-sectional views of the interior of the double andsingle stator pair, respectively, motor sliced perpendicular to themotor shaft 216. The motor features a three phase arrangement, withthree sets of stator windings 615 that are mounted on the stationarymounting shaft 216 and three rows of very high strengthNeodymium-iron-boron magnets 610. The magnets 610 can be arranged inthree, six or nine discs which turn with the outside drum of the motor,or can be directly fastened to the inside of the outer drum for maximummechanical advantage. As shown in FIG. 7 a, the “X” phase 36 pole 615stator assembly 630 is mounted to the shaft 216 through its mountingdisc 620. The 36 Neodymium Permanent Magnets 610 are fastened to theinside 655 of the motor outer drum assembly 650. These Permanent Magnetsare alternately “North” and “South” magnetic orientation.

FIG. 8 is another cross-sectional perspective view of the motor 214,this time sliced parallel to the motor mounting shaft 216. Three sets ofstator electromagnet assemblies (X, Y, Z) are each mounted to the shaft216 through their mounting discs 620. The three sets of 36 permanentmagnets 610 are attached to the inside of the outer drum assembly 250with both epoxy and mechanical fasteners. Individual electromagnet polesare identified as 615. The offset differences of the three sets ofelectromagnet stators (X, Y, Z) are 0.0, −6.66, and −13.3 degrees,respectively. The drum arrangement is shown in FIGS. 7-9 for simplicity,although alternatively, the disc arrangement can also be substituted.

Whereas AC induction motors have very poor starting torque andefficiency, the motor described for use in the present inventionactually has its maximum torque at start and at very low speed making itan ideal component for a tracked vehicle, which often is operated forlong periods of time at crawling speeds. The name frequently given tothis type of vehicle is “crawler tractor”. The motor of the presentinvention is well suited for this application, giving off minimum heatat low speed.

According to the present invention, at any given moment, at least twosets of 36 poles each are energized. Generally one set is pulling(attraction of poles), one set is pushing (repulsion of poles) and oneset is approaching zero switchover. This results in very high torquelevels. Full torque and power is available in either direction, meaningthat the motors can be interchangeably used for right hand and left handinstallations. Turning, speed control and braking is handledelectronically, with electronic torque matching between pairs of drivingmotors in the track assemblies. Only parking brakes are added. Thestationary motor mounting shaft 216 is hollow on one end 218, permittingthe power wires, position feedback sensor wires, and coolant lines tointerconnect, while allowing the motor to be sealed against outsideelements.

Three discs 615 are keyed to the inner shaft 216, each holding multiplepole high strength electromagnets 610. Increasing the number of poles615 increases the starting torque at the expense of top speed. In thisexample, 36 poles 615 are used, although an alternative even number canbe used. The motor according to this example produces approximately30,000 Foot pounds of starting torque with a top speed of approximately200 RPM's at 60 HZ input. This translates to a top vehicle speed ofapproximately 20 MPH at 60 Hertz, or more with a higher top Hertz input.Alternative combinations of torque and speed are available by varyingthe number of poles used.

As shown in FIG. 9, permanent Magnets can be arranged every 10 degreesin a linear, end to end configuration and the 36 stator windings arealso spaced every 10 degrees. The three phases of power are accommodatedby staggering the keying of the stator discs as:

Phase “X”—reference to zero degrees offset

Phase “Y”—reference to −6.66 degrees offset lagging for a 36 pole stator

Phase “Z”—reference to −13.32 degrees offset lagging for a 36 polestator

For high efficiency at any operating speed and for zero speed start, itis necessary for the controlling electronics to “know” the exactlocation of the permanent magnets with reference to the statorelectromagnets, so that the proper coils are energized and in the propermagnetic direction.

FIG. 10 is a schematic block diagram of the drive control electronics700 according to the present invention. This position sensing isaccomplished using Hall effect sensors which pick up the position of theactual Neo permanent magnets mounted to the motor outer drum. Thesensors include a left and right front sensors 702 and left and rightrear sensors 704. The output of each sensor has both voltage andpolarity output, which is communicated to front and rear motor controlelectronics 712 and 714, respectively, through wires routed through thehollow cavity 218 in the wheel mounting shaft 216. In this example, thefront motor controllers 712 function as slave motor controllers and therear motor controllers 714 function as master motor controllers.Although Hall effect sensors are preferred due to the ruggedness andtheir imperviousness to liquids or dust, other types of sensors can besubstituted, such as resolvers and digitizers.

The electromagnets 610 are constructed of very high magneticpermeability material, and are wound with very low ohmic resistance wirewindings. Due to the size of the assembly, the electromagnets 610 areconstructed in bi-polar pairs. Thus, 18 pairs are used in each 36 poleassembly. The windings are, depending on speed and torque desired,connected in series or in parallel, with automatic switchover at apredetermined speed.

As shown in FIG. 10, the motor drive electronics 700 consists of controlelectronics 712 and 714, and pilot and navigational inputs 730. Thecontrol electronics protects the motors and vehicle from over speed,overload, too tight of turns at high speed, to high “G” forces overrough terrain. Pilot inputs 735 are simplified to speed, direction, andsteering. The control electronics 700 can also navigate via GPS (notshown) to a particular course or a particular destination.

As shown in FIG. 10, each of four motor coil sets is powered by a pulsewidth modulated (PWM) motor control 702 and 704, and is provided withposition feedback from an associated set of Hall effect sensors 702 and704. Since two Direct Drive motors are contained in each rubber drivingtrack 500, the rear motor control 714 is considered a “master” and islinked to the front motor control 712, which is considered a “slave”.This allows precise load sharing via “torque matching”.

In this example, all four motor controllers 712 and 714 are powered fromthe DC bus, which receives its electrical power from the electricalpower source 740. The electrical power source 740 can be a genset, fuelcells, solar cells, or commercial power grid. If the source is AC, it isrectified to DC through a six pole bridge rectifier and a controller.Interconnections allow “get home capability” with any motor or motorControl to be inoperative.

The battery pack 745 can power the vehicle alone until it needs to berecharged or can power the vehicle in tandem with the main power source740 as a hybrid. When the vehicle is braking, the generated power fromthe wheel motors is recovered and used to charge the battery pack 745.If the battery is fully charged, the voltage of the DC bus will raiseslightly. The brake PWM Controller 750 shunts the excess voltage througha large exterior braking resistor 755 automatically.

The control system 810 in the pilothouse 800 takes pilot input fordirection of travel, speed, turning, or braking, and limits the powerinput to prevent damage or overload. This is commonly described as “flyby wire”. The precise speed and sync capability of these motors allowsprecise steering inputs, through feedback and regulated by the controlsystem. The control system 730 also manages the DC bus voltage, batteryusage and charging management and braking resistor power management.Power management for hybrid operation is also controlled. Additionalinputs allow for fully coupled autopilot operation, with navigationreferences to gyro and GPS input.

FIGS. 11 a and 11 b shows a rear and side view, respectively, of anexample of a pilot control stick 900 connected with the control system.FIG. 11 c is a schematic diagram showing an example of the electricalconnections of the speed steering pilot's control. In this example,moving either, or both, levers forward makes the vehicle accelerate in aforward direction. Pulling one or both of the levers rearward makes thevehicle stop, then move backward. Twisting one lever forward and oneaft, makes the vehicle turn in the direction of the twist.

The actual wiring of the electromagnetic poles is connected in groups ofat least two per phase. FIG. 12 shows the low speed/high torqueconfiguration, which places all 36 poles of each phase in series.Compared to the High Speed/Low Torque parallel connections, this givesdouble the amperage through each coil because the motor PWM controlleris current limited, and the reverse EMF is low at low speed. Theconfiguration shown in FIG. 12 doubles starting/low speed torque. Theactual switching is done by RL1, RL2, RL3, which can be eithermechanical relays or solid state devices. Although they are shownlocated near the windings, in practice they are located outside themotor.

FIG. 13 shows RL1, RL2, RL3 in high speed, half torque configurationwith the relays energized. Since the reverse EMF is proportional tomotor speed, at higher speed the reverse EMF substantially limits theactual current through the stator windings. The parallel configurationdoubles the input voltage less the reverse RMF and makes realistictorque available at higher speeds. The configuration shown in FIG. 13increases the top speed of the vehicle.

Although the description describes the novel invention for use in oilexploration on environmentally sensitive land such as frozen tundra, theinvention can have other applications. For example, the invention canhave application in military applications such in different environmentssuch as sand and desert conditions. The invention can have applicationin agricultural uses such as for tractors, and farm equipment.

While the invention has been described, disclosed, illustrated and shownin various terms of certain embodiments or modifications which it haspresumed in practice, the scope of the invention is not intended to be,nor should it be deemed to be, limited thereby and such othermodifications or embodiments as may be suggested by the teachings hereinare particularly reserved especially as they fall within the breadth andscope of the claims here appended.

1. A tracked vehicle, comprising: a track module frame; at least twoelectrically driven track wheels connected with the track module frame,each electrically driven track wheel comprising: a driving track wheelhaving built in cogs on an outer surface for driving a track; apermanent magnet electric motor drive having a stationary mounting shaftrunning through the brushless DC motor for connecting the electricallydriven wheel to a frame of the tracked vehicle, wherein the permanentmagnet electric motor drive is coupled within the driving track wheel todevelop rotational torque for rotating the driving track wheel; aninternal direct drive pulse modulated DC integral motor to provide twicethe power available to the ground and the actual tensile stress on theat least two flexible tracks is approximately evenly distributed; andtwo end plates covering each end of the driving track wheel enclosingthe brushless DC motor therein, wherein the driving track wheel directlytransmits thrust loads directly to the mounting shaft; at least twoflexible tracks, one on each sides of the track module frame and beingrotated by the at least two electrically driven track wheels, whereinthe at least two flexible tracks have the ability to resiliently trackuneven surfaces to increase track life and minimizing disturbance to theterrain; and a suspension system for connecting the track module frameto a chassis of the tracked vehicle, wherein shock encountered by thetrack module frame are not transmitted to the vehicle chassis.
 2. Thetracked vehicle of claim 1, further comprising: independent control forvertical movement, tilting (angular) movement and torsional movement. 3.The tracked vehicle of claim 1, further comprising: an adjustable heightcontrol for adjusting a ground clearance of the track vehicle tocompensate for different terrain slopes to provide a smoother, saferride, with bump absorption, improved stability, and a faster allowablespeed of navigation over uneven surfaces.
 4. The tracked vehicle ofclaim 1, wherein each one of the at lest two track wheels comprise: adriving track wheel having built in cogs for driving one of the at leasttwo tracks; and an individual electrical motor coupled within thedriving track wheel to develop rotational torque for rotating thedriving track wheel.
 5. The tracked vehicle of claim 1, wherein each ofthe at least two flexible tracks comprise: plural belt cogs on aninterior surface of the flexible track to mate with the built in cogs onthe driving track wheel, wherein the driving track wheel has overapproximately 180 degrees of contact between the built in cogs and thematching plural belt cogs.
 6. The tracked vehicle of claim 1, furthercomprising: a second track frame modules for driving at least one of atrailer and a second tracked vehicle Banning a tracked trailer train. 7.The tracked vehicle of claim 1 wherein the track module frame comprises:at least two interchangeable self contained track frame modules.
 8. Atracked vehicle, comprising: a track module frame; at least twoelectrically driven track wheels connected with the track module frame,each electrically driven track wheel comprising: a driving track wheelhaving built in cogs on an outer surface for driving a track; apermanent magnet electric motor drive having a stationary mounting shaftrunning through the brushless DC motor for connecting the electricallydriven wheel to a frame of the tracked vehicle, wherein the permanentmagnet electric motor drive is coupled within the driving track wheel todevelop rotational torque for rotating the driving track wheel; and twoend plates covering each end of the driving track wheel enclosing thebrushless DC motor therein, wherein the driving track wheel directlytransmits thrust loads directly to the mounting shaft; at least twoflexible tracks, one on each sides of the track module frame and beingrotated by the at least two electrically driven track wheels, whereinthe at least two flexible tracks have the ability to resiliently trackuneven surfaces to increase track life and minimizing disturbance to theterrain; a suspension system for connecting the track module frame to achassis of the tracked vehicle; and independent control for verticalmovement, tilting (angular) movement and torsional movement, whereinshock encountered by the track module frame are not transmitted to thevehicle chassis.
 9. The tracked vehicle of claim 8, further comprising:an adjustable height control for adjusting a ground clearance of thetrack vehicle to compensate for different terrain slopes to provide asmoother, safer ride, with bump absorption, improved stability, and afaster allowable speed of navigation over uneven surfaces.
 10. Thetracked vehicle of claim 8, wherein each one of the at least two trackwheels comprise: a driving track wheel having built in cogs for drivingone of the at least two tracks; and an individual electrical motorcoupled within the driving track wheel to develop rotational torque forrotating the driving track wheel.
 11. The tracked vehicle of claim 8,wherein each of the at least two flexible tracks comprise: plural beltcogs on an interior surface of the flexible track to mate with the builtin cogs on the driving track wheel, wherein the driving track wheel hasover approximately 180 degrees of contact between the built in cogs andthe matching plural belt cogs.
 12. The tracked vehicle of claim 8,wherein each of the at least two track wheels comprise: an internaldirect drive pulse modulated DC integral motor to provide twice thepower available to the ground and the actual tensile stress on the atleast two flexible tracks is more evenly distributed.
 13. The trackedvehicle of claim 8, further comprising: a second track frame modules fordriving at least one of a trailer and a second tracked vehicle forming atracked trailer train.
 14. The tracked vehicle of claim 8, wherein thetrack module frame comprises: at least two interchangeable selfcontained track frame modules.
 15. A tracked vehicle, comprising: atrack module frame; at least two electrically driven track wheelsconnected with the track module frame, each electrically driven trackwheel comprising: a driving track wheel having built in cogs on an outersurface for driving a track; a permanent magnet electric motor drivehaving a stationary mounting shaft running through the brushless DCmotor for connecting the electrically driven wheel to a frame of thetracked vehicle, wherein the permanent magnet electric motor drive iscoupled within the driving track wheel to develop rotational torque forrotating the driving track wheel; and two end plates covering each endof the driving track wheel enclosing the brushless DC motor therein,wherein the driving track wheel directly transmits thrust loads directlyto the mounting shaft; at least two flexible tracks, one on each sidesof the track module frame and being rotated by the at least twoelectrically driven track wheels, wherein the at least two flexibletracks have the ability to resiliently track uneven surfaces to increasetrack life and minimizing disturbance to the terrain; a suspensionsystem for connecting the track module frame to a chassis of the trackedvehicle; and an adjustable height control for adjusting a groundclearance of the track vehicle to compensate for different terrainslopes to provide a smoother, safer ride, with bump absorption, improvedstability, and a faster allowable speed of navigation over unevensurfaces, wherein shock encountered by the track module frame are nottransmitted to the vehicle chassis.
 16. The tracked vehicle of claim 15,further comprising: independent control for vertical movement, tilting(angular) movement and torsional movement.
 17. The tracked vehicle ofclaim 15, wherein each one of the at least two track wheels comprise: adriving track wheel having built in cogs for driving one of the at leasttwo tracks; and an individual electrical motor coupled within thedriving track wheel to develop rotational torque for rotating thedriving track wheel.
 18. The tracked vehicle of claim 15, wherein eachof the at least two flexible tracks comprise: plural belt cogs on aninterior surface of the flexible track to mate with the built in cogs onthe driving track wheel, wherein the driving track wheel has overapproximately 180 degrees of contact between the built in cogs and thematching plural belt cogs.
 19. The tracked vehicle of claim 15, whereineach of the at least two track wheels comprise: an internal direct drivepulse modulated DC integral motor to provide twice the power availableto the ground and the actual tensile stress on the at least two flexibletracks is more evenly distributed.
 20. The tracked vehicle of claim 15,further comprising: a second track frame modules for driving at leastone of a trailer and a second tracked vehicle forming a tracked trailertrain.
 21. The tracked vehicle of claim 15, wherein the track moduleframe comprises: at least two interchangeable self contained track framemodules.